1. Field of the Invention
The present invention generally relates to the field of high surface area nanoparticles and applications thereof.
2. Description of Related Art
Nanotechnology has generated a great impact on materials, microelectronics, computing, pharmaceuticals, medicinal, environmental, energy and the chemical industries. Nanoparticles have long been recognized as having enhanced chemical and physical properties compared with their bulk forms. They can be applied as building blocks for fabrication of an assortment of valuable materials (Xia et al., 2000). They can be of various sizes, crystallinity, morphology, and chemical compositions. Nanoparticles can be composed of a variety of materials, with silica being one of the best known examples (see, e.g., Gole et al., 2003). The need for silica nanoparticles, particularly nanospheres with specific dimensions and morphology has grown because of the numerous industrial applications.
The field of silica nanospheres has expanded, particularly after the emergence of Stober's innovative method for the synthesis of monodisperse silica by hydrolyzing tetraethylorthosilicate (TEOS) (Stober et al., 1968). Following the inception of template-directed synthesis of mesoporous silica (Kresge et al., 1992), there has been a great deal of interest in controlling the morphology and pore size of nanospheres (Huo et al., 1994; Tanev and Pinnavaia, 1995; Zhao et al., 1998; Carlsson et al., 1999). Using template techniques, a variety of mesoporous as well as nano-silica materials with a wide range of morphology were synthesized (see, e.g., Cha et al., 2000; Sakamoto et al., 2000; Lu et al., 2001; Finnefrock et al., 2001; Yu et al., 2002; Che et al., 2003; Che et al., 2004; Yokoi et al., 2006; Gao et al., 2006; Bao et al., 2007; Han et al., 2009; Suzuki et al., 2009; Meng et al., 2009; Suzuki et al., 2010). These materials have found a wide application in catalysis (Davis et al., 2002; Corma and Garcia, 2008; Weckhuysen, 2009).
The effectiveness of nanoparticles in catalysis is primarily due to their microstructure, which allows good dispersion of active catalytic molecules on the large internal surfaces and pores. However, difficulty with sintering of active metals due to limited accessibility of active sites inside some pores has limited the applicability of nanoparticles in catalysis, particularly in instances where significant mass transport is essential and high surface area of nanoparticles can be potentially used as an alternative (Gellman, 2009; Joo et al., 2009; Schlögl and Hamid, 2004; Reetz, 2008).
Thus, there is the need for nanoparticles with a high surface area. Such nanoparticles would result in improved activity and stability of catalytic molecules, and would find application in other areas where a high surface area is desirable.